1. Technical Field
The present invention relates to an organic anti-reflection coating composition for preventing reflection at the undercoat layer and preventing standing wave during a lithography process, and having a high dry etching rate. More particularly, the invention relates to a novel polymer which can be used in the production of an organic anti-reflection coating that is useful for semiconductor ultrafine patterning using an ArF excimer laser, a light absorbent, and an organic anti-reflection coating composition containing these.
The present invention also relates to a method for patterning of semiconductor devices using the organic anti-reflection coating composition.
2. Description of the Related Art
The recent high integration of semiconductor devices has led to a demand for ultrafine patterns with a line width of 0.10 micrometers or less in the production of ultra-LSI and the like, and a lithography process using light having a smaller wavelength than the conventionally used light for exposure having a wavelength in the region of g-ray or i-ray, is also demanded. Thus, microlithography processes using KrF excimer laser or ArF excimer laser are currently used in the processes for producing semiconductor devices.
As the size of the pattern of semiconductor devices is ever decreasing, only when the reflection rate is maintained to be less than 1% at maximum during the progress of the exposure process, uniform pattern can be obtained, an adequate process margin can be obtained, and a desired yield can be achieved. Therefore, a technology of disposing underneath a photoresist, an organic anti-reflection coating containing organic molecules which are capable of absorbing light, in order to reduce the reflection rate as far as possible, and thereby regulating the reflection rate to prevent reflection at the undercoat layer and to remove standing wave, has become important.
Accordingly, the organic anti-reflection coating composition should satisfy the following requirements.
First, the organic anti-reflection coating composition should contain a material which is capable of absorbing light in the region of the wavelength of the exposure light source, in order to prevent reflection at the undercoat layer. Secondly, the anti-reflection coating should not be solubilized and destroyed by the solvent of a photoresist during the process of laminating the anti-reflection coating and then laminating a photoresist. For this, the anti-reflection coating must be designed to have a thermally curable structure, and curing should be accelerated by carrying out a baking process after coating in the process for laminating anti-reflection coating. Thirdly, the anti-reflection coating should be able to be etched faster than the photoresist in the upper part, so as to reduce a loss of the photoresist resulting from etching of the undercoat layer. Fourthly, the anti-reflection coating composition should not be reactive to the photoresist in the upper part. Also, compounds such as amine or acid should migrate to the photoresist layer, because these compounds may cause deformation in the photoresist pattern, such as footing or undercoat in particular. Fifthly, the anti-reflection coating composition should have optical properties that are appropriate for various exposure processes in accordance with various substrates, that is, an appropriate refractive index and an absorption coefficient, and also should have good adhesiveness to the substrate and the photoresist.
However, under the current situation, an anti-reflection coating which is satisfactory in the process for ultrafine patterning using ArF light, has not been developed so far. Therefore, in order to prevent standing wave and reflection generated upon exposure, and to eliminate the back-diffraction at the undercoat layer and the influence of reflected light, development of an organic anti-reflection material having large absorption for a specific wavelength is considered as an urgent problem to be solved.